1. Field of the Invention
The present invention relates to a manufacturing method for manufacturing a resin composition containing fine paper powder in which fine paper powder is evenly dispersed and contained in resin.
2. Description of the Related Art
Nowadays, large amounts of waste paper are discarded from offices, publication houses, paper manufacturing companies and the like. In general, at a stage during manufacturing of paper from wood or the like, paper is subjected to a high degree of processing in order to render cellulose fibers finely softened, such that paper is a functional material having a value-added structure. Therefore, waste paper is originally a functional material having a value-added structure. Moreover, waste paper is a material that is effectively zero in terms of its environmental impact. Consequently, proposals have been made for using resin compositions containing paper, in which pulverized waste paper is mixed, for molding process materials.
For example, in Japanese Patent Laid-open No. 10-138241, there has been disclosed a resin pellet containing paper in which a composite paper having a polyethylene resin layer on at least one surface thereof is shredded into shredded paper components of about 1 mm to 5 mm square, and the shredded paper components are mixed at 50% by weight or greater with a synthetic resin component of polyethylene or the like to yield the resin pellet containing paper.
In Japanese Patent Laid-open No. 2001-181511, there has been disclosed a resin composition containing paper for use in molding processes, which contains in excess of 50% by weight and at or below 70% by weight of a low combustion heat component in powder form consisting mainly of paper powder and having a particle diameter of 50 μm or greater and 200 μm or less made by grinding waste paper or the like, and 30% or more by weight and less than 50% by weight of a high combustion heat component made up mainly from a thermoplastic resin.
However, paper having no fluidity disrupts the smooth flow of molten resins. Therefore, whether the resin pellet containing paper disclosed in Japanese Patent Laid-open No. 10-138241 or the resin composition containing paper for use in molding processes disclosed in Japanese Patent Laid-open No. 2001-181511 is used to produce a complex molded article by injection molding, defects such as filling failures occur easily, and transferability is also deteriorated, which makes it impossible to obtain molded products of a high quality.